This is a note to let you know that I've just added the patch titled
cifs: skip extra NULL byte in filenames
to the 5.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
cifs-skip-extra-null-byte-in-filenames.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a1d2eb51f0a33c28f5399a1610e66b3fbd24e884 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <pc@xxxxxx>
Date: Fri, 19 Aug 2022 17:00:19 -0300
Subject: cifs: skip extra NULL byte in filenames
From: Paulo Alcantara <pc@xxxxxx>
commit a1d2eb51f0a33c28f5399a1610e66b3fbd24e884 upstream.
Since commit:
cifs: alloc_path_with_tree_prefix: do not append sep. if the path is empty
alloc_path_with_tree_prefix() function was no longer including the
trailing separator when @path is empty, although @out_len was still
assuming a path separator thus adding an extra byte to the final
filename.
This has caused mount issues in some Synology servers due to the extra
NULL byte in filenames when sending SMB2_CREATE requests with
SMB2_FLAGS_DFS_OPERATIONS set.
Fix this by checking if @path is not empty and then add extra byte for
separator. Also, do not include any trailing NULL bytes in filename
as MS-SMB2 requires it to be 8-byte aligned and not NULL terminated.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 7eacba3b00a3 ("cifs: alloc_path_with_tree_prefix: do not append sep. if the path is empty")
Signed-off-by: Paulo Alcantara (SUSE) <pc@xxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/cifs/smb2pdu.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2571,19 +2571,15 @@ alloc_path_with_tree_prefix(__le16 **out
path_len = UniStrnlen((wchar_t *)path, PATH_MAX);
- /*
- * make room for one path separator between the treename and
- * path
- */
- *out_len = treename_len + 1 + path_len;
+ /* make room for one path separator only if @path isn't empty */
+ *out_len = treename_len + (path[0] ? 1 : 0) + path_len;
/*
- * final path needs to be null-terminated UTF16 with a
- * size aligned to 8
+ * final path needs to be 8-byte aligned as specified in
+ * MS-SMB2 2.2.13 SMB2 CREATE Request.
*/
-
- *out_size = roundup((*out_len+1)*2, 8);
- *out_path = kzalloc(*out_size, GFP_KERNEL);
+ *out_size = roundup(*out_len * sizeof(__le16), 8);
+ *out_path = kzalloc(*out_size + sizeof(__le16) /* null */, GFP_KERNEL);
if (!*out_path)
return -ENOMEM;
Patches currently in stable-queue which might be from pc@xxxxxx are
queue-5.19/cifs-skip-extra-null-byte-in-filenames.patch
